blocks|key|1061545|text|require+'json'
{"foo"+=>+"bar"}.to_json
#+=>+"{\"foo\":\"bar\"}"|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1061546|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code>require 'json'
{"foo" =&gt; "bar"}.to_json
# =&gt; "{\"foo\":\"bar\"}"
</code></pre>

blocks|key|847182|text|如果渲染性能很重要，您可能还想看看yajl-ruby，它是一个到C+yajl库的绑定。该序列化API如下所示：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|847183|require+'yajl'
Yajl::Encoder.encode({"foo"+=>+"bar"})+#=>+"{\"foo\":\"bar\"}"|code-block|syntax|javascript|847184|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/brianmario/yajl-ruby|1|http://lloyd.github.com/yajl/^0|H|9|0|Y|4|1|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]|$A|W|B|X|1|Y]]|C|$]]|$1|D|3|E|5|F|7|Z|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|10|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]|Q|$5|L|M|N|C|$O|R]]]]

If rendering performance is critical, you might also want to look at <a href="https://github.com/brianmario/yajl-ruby" rel="noreferrer">yajl-ruby</a>, which is a binding to the C <a href="http://lloyd.github.com/yajl/" rel="noreferrer">yajl</a> library. The serialization API for that one looks like:

<pre><code>require 'yajl'
Yajl::Encoder.encode({"foo" =&gt; "bar"}) #=&gt; "{\"foo\":\"bar\"}"
</code></pre>

blocks|key|847266|text|为了使JSON库可用，您可能需要从包管理器安装libjson-ruby。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|847267|要使用'json‘库：|847268|require+'json'|code-block|syntax|javascript|847269|要将对象转换为JSON+(这3种方法是等效的)：|847270|JSON.dump+object+#returns+a+JSON+string
JSON.generate+object+#returns+a+JSON+string
object.to_json+#returns+a+JSON+string|847271|将JSON文本转换为对象(这两种方法等效)：|847272|JSON.load+string+#returns+an+object
JSON.parse+string+#returns+an+object|847273|对于来自您自己的类的对象来说，这会有点困难。对于下面的类，to_json将生成类似于"\"#<A:0xb76e5728>\""的内容。|847274|class+A
++++def+initialize+a=[1,2,3],+b='hello'
++++++++@a+=+a
++++++++@b+=+b
++++end
end|847275|这可能是不可取的。要有效地将对象序列化为JSON，您应该创建自己的to_json方法。为此，from_json类方法将非常有用。你可以像这样扩展你的类：|847276|class+A
++++def+to_json
++++++++{'a'+=>+@a,+'b'+=>+@b}.to_json
++++end
++++def+self.from_json+string
++++++++data+=+JSON.load+string
++++++++self.new+data['a'],+data['b']
++++end
end|847277|你可以通过继承一个'JSONable‘类来实现自动化：|847278|class+JSONable
++++def+to_json
++++++++hash+=+{}
++++++++self.instance_variables.each+do+%7Cvar%7C
++++++++++++hash[var]+=+self.instance_variable_get+var
++++++++end
++++++++hash.to_json
++++end
++++def+from_json!+string
++++++++JSON.load(string).each+do+%7Cvar,+val%7C
++++++++++++self.instance_variable_set+var,+val
++++++++end
++++end
end|847279|然后，可以使用object.to_json序列化到JSON，并使用object.from_json!+string将保存为JSON字符串的保存状态复制到对象。|847280|entityMap^0|N|C|0|0|0|0|0|0|0|16|L|0|0|0|0|0|0|7|E|X|O|0^^$0|@$1|2|3|4|5|6|7|1A|8|@$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|1D|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|1E|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1F|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|1G|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|1H|8|@]|D|@]|E|$]]|$1|S|3|T|5|J|7|1I|8|@]|D|@]|E|$K|L]]|$1|U|3|V|5|6|7|1J|8|@$9|1K|A|1L|B|C]]|D|@]|E|$]]|$1|W|3|X|5|J|7|1M|8|@]|D|@]|E|$K|L]]|$1|Y|3|Z|5|6|7|1N|8|@]|D|@]|E|$]]|$1|10|3|11|5|J|7|1O|8|@]|D|@]|E|$K|L]]|$1|12|3|13|5|6|7|1P|8|@]|D|@]|E|$]]|$1|14|3|15|5|J|7|1Q|8|@]|D|@]|E|$K|L]]|$1|16|3|17|5|6|7|1R|8|@$9|1S|A|1T|B|C]|$9|1U|A|1V|B|C]]|D|@]|E|$]]|$1|18|3|-4|5|6|7|1W|8|@]|D|@]|E|$]]]|19|$]]

For the JSON library to be available, you may have to install <code>libjson-ruby</code> from your package manager.

To use the 'json' library:

<pre><code>require 'json'
</code></pre>

To convert an object to JSON (these 3 ways are equivalent):

<pre><code>JSON.dump object #returns a JSON string
JSON.generate object #returns a JSON string
object.to_json #returns a JSON string
</code></pre>

To convert JSON text to an object (these 2 ways are equivalent):

<pre><code>JSON.load string #returns an object
JSON.parse string #returns an object
</code></pre>

It will be a bit more difficult for objects from your own classes. For the following class, to_json will produce something like <code>"\"#&lt;A:0xb76e5728&gt;\""</code>.

<pre><code>class A
 def initialize a=[1,2,3], b='hello'
 @a = a
 @b = b
 end
end
</code></pre>

This probably isn't desirable. To effectively serialise your object as JSON, you should create your own to_json method. To go with this, a from_json class method would be useful. You could extend your class like so:

<pre><code>class A
 def to_json
 {'a' =&gt; @a, 'b' =&gt; @b}.to_json
 end
 def self.from_json string
 data = JSON.load string
 self.new data['a'], data['b']
 end
end
</code></pre>

You could automate this by inheriting from a 'JSONable' class:

<pre><code>class JSONable
 def to_json
 hash = {}
 self.instance_variables.each do |var|
 hash[var] = self.instance_variable_get var
 end
 hash.to_json
 end
 def from_json! string
 JSON.load(string).each do |var, val|
 self.instance_variable_set var, val
 end
 end
end
</code></pre>

Then you can use <code>object.to_json</code> to serialise to JSON and <code>object.from_json! string</code> to copy the saved state that was saved as the JSON string to the object.

blocks|key|847326|text|你使用的是什么版本的Ruby？ruby+-v会告诉你的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|847327|如果是1.9.2，则为JSON+is+included+in+the+standard+library。|847328|如果你使用的是1.8，那么执行gem+install+json，它就会安装。然后，在你的代码中这样做：|847329|require+'rubygems'
require+'json'|code-block|syntax|javascript|847330|然后将to_json附加到一个对象，就可以开始了：|847331|asdf+=+{'a'+=>+'b'}+#=>+{"a"=>"b"}
asdf.to_json+#=>+"{"a":"b"}"|847332|entityMap|0|LINK|mutability|MUTABLE|url|http://ruby-doc.org/ruby-1.9/classes/JSON.html^0|F|7|0|B|14|0|0|F|G|0|0|3|7|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@$9|11|A|12|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|13|8|@]|D|@$9|14|A|15|1|16]]|E|$]]|$1|H|3|I|5|6|7|17|8|@$9|18|A|19|B|C]]|D|@]|E|$]]|$1|J|3|K|5|L|7|1A|8|@]|D|@]|E|$M|N]]|$1|O|3|P|5|6|7|1B|8|@$9|1C|A|1D|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|L|7|1E|8|@]|D|@]|E|$M|N]]|$1|S|3|-4|5|6|7|1F|8|@]|D|@]|E|$]]]|T|$U|$5|V|W|X|E|$Y|Z]]]]

What version of Ruby are you using? <code>ruby -v</code> will tell you. 

If it's 1.9.2, <a href="http://ruby-doc.org/ruby-1.9/classes/JSON.html" rel="noreferrer">JSON is included in the standard library</a>. 

If you're on 1.8.something then do <code>gem install json</code> and it'll install. Then, in your code do:

<pre><code>require 'rubygems'
require 'json'
</code></pre>

Then append <code>to_json</code> to an object and you're good to go:

<pre><code>asdf = {'a' =&gt; 'b'} #=&gt; {"a"=&gt;"b"}
asdf.to_json #=&gt; "{"a":"b"}"
</code></pre>

blocks|key|847382|text|如果您使用的是1.9.2或更高版本，那么只需使用to_json就可以将散列和数组转换为嵌套的JSON对象。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|847383|{a:+[1,2,3],+b:+4}.to_json|code-block|syntax|javascript|847384|在Rails中，您可以对活动记录对象调用to_json。您可以传递:include和:only参数来控制输出：|847385|@user.to_json+only:+[:name,+:email]|847386|您还可以在AR关系上调用to_json，如下所示：|847387|User.order("id+DESC").limit(10).to_json|847388|你不需要导入任何东西，它就像你希望的那样工作。|847389|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|W|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|Y|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

If you're using 1.9.2 or above, you can convert hashes and arrays to nested JSON objects just using to_json. 

<pre><code>{a: [1,2,3], b: 4}.to_json
</code></pre>

In Rails, you can call to_json on Active Record objects. You can pass :include and :only parameters to control the output:

<pre><code>@user.to_json only: [:name, :email]
</code></pre>

You can also call to_json on AR relations, like so:

<pre><code>User.order("id DESC").limit(10).to_json
</code></pre>

You don't need to import anything and it all works exactly as you'd hope.

blocks|key|1061777|text|查看Oj。当涉及到将任何旧对象转换为JSON时，有一些陷阱，但Oj可以做到这一点。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1061778|require+'oj'

class+A
++++def+initialize+a=[1,2,3],+b='hello'
++++++++@a+=+a
++++++++@b+=+b
++++end
end

a+=+A.new
puts+Oj::dump+a,+:indent+=>+2|code-block|syntax|javascript|1061779|这将输出以下内容：|1061780|{
++"%5Eo":"A",
++"a":[
++++1,
++++2,
++++3
++],
+"b":"hello"
}|1061781|请注意，%5Eo用于指定对象的类，并且用于帮助反序列化。要省略%5Eo，请使用:compat模式：|style|CODE|1061782|puts+Oj::dump+a,+:indent+=>+2,+:mode+=>+:compat|1061783|输出：|1061784|{
++"a":[
++++1,
++++2,
++++3
++],
++"b":"hello"
}|1061785|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/ohler55/oj^0|2|2|0|0|0|0|0|4|2|T|2|Z|7|0|0|0|0^^$0|@$1|2|3|4|5|6|7|14|8|@]|9|@$A|15|B|16|1|17]]|C|$]]|$1|D|3|E|5|F|7|18|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|19|8|@]|9|@]|C|$]]|$1|K|3|L|5|F|7|1A|8|@]|9|@]|C|$G|H]]|$1|M|3|N|5|6|7|1B|8|@$A|1C|B|1D|O|P]|$A|1E|B|1F|O|P]|$A|1G|B|1H|O|P]]|9|@]|C|$]]|$1|Q|3|R|5|F|7|1I|8|@]|9|@]|C|$G|H]]|$1|S|3|T|5|6|7|1J|8|@]|9|@]|C|$]]|$1|U|3|V|5|F|7|1K|8|@]|9|@]|C|$G|H]]|$1|W|3|-4|5|6|7|1L|8|@]|9|@]|C|$]]]|X|$Y|$5|Z|10|11|C|$12|13]]]]

Check out <a href="https://github.com/ohler55/oj" rel="noreferrer">Oj</a>. There are gotchas when it comes to converting any old object to JSON, but Oj can do it.

<pre><code>require 'oj'

class A
 def initialize a=[1,2,3], b='hello'
 @a = a
 @b = b
 end
end

a = A.new
puts Oj::dump a, :indent =&gt; 2
</code></pre>

This outputs:

<pre><code>{
 "^o":"A",
 "a":[
 1,
 2,
 3
 ],
 "b":"hello"
}
</code></pre>

Note that <code>^o</code> is used to designate the object's class, and is there to aid deserialization. To omit <code>^o</code>, use <code>:compat</code> mode:

<pre><code>puts Oj::dump a, :indent =&gt; 2, :mode =&gt; :compat
</code></pre>

Output:

<pre><code>{
 "a":[
 1,
 2,
 3
 ],
 "b":"hello"
}
</code></pre>

blocks|key|1061807|text|实际上，有一个名为Jsonable的gem，https://github.com/treeder/jsonable。真的很甜蜜。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1061808|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/treeder/jsonable^0|M|Z|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Actually, there is a gem called Jsonable, <a href="https://github.com/treeder/jsonable" rel="nofollow">https://github.com/treeder/jsonable</a>. It's pretty sweet.

blocks|key|1061847|text|要让内置的类(如数组和散列)支持as_json和to_json，您需要require+'json/add/core'+(有关详细信息，请参阅readme+)|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1061848|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/flori/json^0|G|7|O|7|Z|N|1Y|6|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|C]]|D|@$9|U|A|V|1|W]]|E|$]]|$1|F|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

To get the build in classes (like Array and Hash) to support <code>as_json</code> and <code>to_json</code>, you need to <code>require 'json/add/core'</code> (see the <a href="https://github.com/flori/json" rel="nofollow">readme</a> for details)

blocks|key|1061875|text|我曾经用过virtus。一个非常强大的工具，可以根据你指定的类创建一个动态的Ruby结构结构。简单的DSL，可以从ruby散列创建对象，有严格的模式。查看it。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1061876|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/solnic/virtus^0|5|6|25|2|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]]|D|@$9|Q|A|R|1|S]]|E|$]]|$1|F|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

I used to <code>virtus</code>. Really powerful tool, allows to create a dynamic Ruby structure structure based on your specified classes. Easy DSL, possible to create objects from ruby hashes, there is strict mode. Check <a href="https://github.com/solnic/virtus" rel="nofollow">it</a> out.

blocks|key|847606|text|因为我自己找了很多，才把Ruby对象序列化为json：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|847607|require+'json'

class+User
++attr_accessor+:name,+:age

++def+initialize(name,+age)
++++@name+=+name
++++@age+=+age
++end

++def+as_json(options={})
++++{
++++++name:+@name,
++++++age:+@age
++++}
++end

++def+to_json(*options)
++++as_json(*options).to_json(*options)
++end
end

user+=+User.new("Foo+Bar",+42)
puts+user.to_json+#=>+{"name":"Foo+Bar","age":42}|code-block|syntax|javascript|847608|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Since I searched a lot myself to serialize a Ruby Object to json: 

<pre><code>require 'json'

class User
 attr_accessor :name, :age

 def initialize(name, age)
 @name = name
 @age = age
 end

 def as_json(options={})
 {
 name: @name,
 age: @age
 }
 end

 def to_json(*options)
 as_json(*options).to_json(*options)
 end
end

user = User.new("Foo Bar", 42)
puts user.to_json #=&gt; {"name":"Foo Bar","age":42}
</code></pre>

blocks|key|847634|text|Jbuilder是一个由rails社区构建的宝石。但它在非rails环境中工作得很好，并且有一组很酷的特性。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|847635|#+suppose+we+have+a+sample+object+as+below
sampleObj.name+#=>+foo
sampleObj.last_name+#=>+bar

#+using+jbuilder+we+can+convert+it+to+json:
Jbuilder.encode+do+%7Cjson%7C
++json.name+sampleObj.name
++json.last_name+sampleObj.last_name
end+#=>+"{:\"name\"+=>+\"foo\",+:\"last_name\"+=>+\"bar\"}"|code-block|syntax|javascript|847636|entityMap|0|LINK|mutability|MUTABLE|url|https://github.com/rails/jbuilder^0|0|8|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

<a href="https://github.com/rails/jbuilder" rel="nofollow">Jbuilder</a> is a gem built by rails community. But it works well in non-rails environments and have a cool set of features.

<pre><code># suppose we have a sample object as below
sampleObj.name #=&gt; foo
sampleObj.last_name #=&gt; bar

# using jbuilder we can convert it to json:
Jbuilder.encode do |json|
 json.name sampleObj.name
 json.last_name sampleObj.last_name
end #=&gt; "{:\"name\" =&gt; \"foo\", :\"last_name\" =&gt; \"bar\"}"
</code></pre>

I'm trying to understand the JSON serialization landscape in Ruby. I'm new to Ruby.

Is there any good JSON serialization options if you are not working with Rails?

That seems to be where this answer goes (to Rails)
<a href="https://stackoverflow.com/questions/3226054/how-to-convert-a-ruby-object-to-json">How to convert a Ruby object to JSON</a>

The json gem seems to make it look like you have to write your own to_json method.
I haven't been able to get to_json to work with arrays and hashes (documentation says it works with these)
Is there a reason the json gem doesn't just reflect over the object and use a default serialization strategy? Isn't this how to_yaml works (guessing here)

Ruby objects and JSON serialization (without Rails)

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JSON

我正在尝试理解Ruby中的JSON序列化环境。我是新来Ruby的。如果您不使用Rails，有没有什么好的JSON序列化选项？这似乎就是这个问题的答案(对于Rails) json gem似乎让它看起来像是您必须编写自己的to_json方法。我还没能让to_json处理数组和散列(文档说它能处理这些)，是不是json ge...

问Ruby对象和JSON序列化(没有Rails)
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